I'd like to ask to who knows well OpenCart 1.5.6 if they have experienced this "structural" issue and if so, if they fixed it or if some recent version fixed it.
Basically, we have customers from all over the world, paying with credit card, Paypal and bank transfer.
Now, I have noticed (please correct me if I am wrong) that if they use Bank Transfer at checkout, the notification emails get appropriately sent in the same language the customer used to create the order.
On the contrary, Paypal and other payment methods that rely on a callback to be called by the Paypal / whatever backend itself, see the notification emails being always delivered in English.
Now, some countries have funny laws that require the order email to be printed and (upon inspection) being read by the local police, who usually don't know a syllabe in English

Does this happen because our OpenCart 1.5.6 installation is broken? Or is it due to the fact that:
- Bank Transfer calls Checkout's "Confirm()" function from within the customer OpenCart and so it "knows" the various session variables including the selected language.
- Paypal and others instead, directly call the callback from a "zero set variables and zero session variables" environment (their backend) and therefore the end user language preference gets lost?